1. Field of the Invention
The present invention relates to a mounting structure of a contact point member in a switch device.
2. Description of the Related Art
For example, a switch device for power window control in a vehicle is structured such that, a slider, in which a contact point member (movable contact point) is mounted to a base member, is provided to a fixed side contact point, wherein the contact point member is connected and disconnected from the fixed side contact point by sliding the slider. A switch device disclosed in Japanese Utility Model Laid-Open No. 6-82738 as such a switch device is structured such that a fixed contact point is formed on an insulating substrate and a knob supported in a casing is rotated to slide a slider coupled to the knob along the insulating substrate, thus connecting and disconnecting a contact point member of the slider from the fixed contact point.
FIG. 12 is a perspective view showing the contact point member in the slider disclosed in Japanese Utility Model No. 6-82738. FIG. 13 is a cross section showing a base member and the contact point member before the contact point member is mounted. FIG. 14A is a longitudinal cross section showing the slider in which the contact point member is mounted in the base member. FIG. 14B is a cross section taken along section B-B in FIG. 14A. A contact point member (movable contact point) 60 is formed of a plate spring member and includes a base portion 61 an outer configuration of which is rectangular as a basic shape, a pair of contact point pieces (resilient contact portions) 62 (62a and 62b) extending from both of right and left end sections of the rear edge in the base portion 61, and a grasping portion 65 extending from the central section of the same rear edge. The contact point piece 62 is formed to extend under the base portion 61 from the bottom portion, that is, to be folded back obliquely in a front direction and has a contact point portion 63 at the tip end bulged in a semi-arc shape toward a side away from the base portion 61. The grasping portion 65 is formed in a rectangular shape to extend backward and to be inclined slightly upward. A rectangular hole 66 is formed in the center of the base portion 61, and an engagement piece (resilient engagement portion) 67 extends in a backward, oblique, and upper direction from the front hole edge.
A base member (contact point holder) 70 is made of resin and has a rectangular outer configuration. The base member 70 is structured such that a front coupling portion 71 thereof is provided with an engagement hole 72 to which a semi spherical engagement portion 81 forming part of the lower end of an engagement rod 80 extending from a side of a rotating knob (not shown) is engaged, and an upper plate portion 74 and side plate portions 75 are formed backward of a vertical wall 71a of the coupling portion 71 to form a box shape to be open downward and backward. Collar portions 76 extend inward from both the side plate portions 75 to be close to the upper plate portion 74 to form a clearance for passing the base portion 61 of the contact point member 60 between the collar portion 76 and the upper plate portion 74. An engagement concave portion 77 is provided in an inner wall of the upper plate portion 74 for engagement to the engagement piece 67 of the contact point member 60, and a shallow guide groove 78 extends from the engagement concave portion 77 to a rear end opening of the base member 70. The guide groove 78 has a width allowing the passing of the engagement piece 67 of the contact point member 60. In the figure, numeral 79 indicates an extrusion hole for molding for forming the collar portions 76.
The grasping portion 65 is gripped by fingers and the base portion 61 of the contact point member 60 is inserted between the upper plate portion 74 and the collar portions 76 in the base member 70 from the front edge to be pressed in forward. Then the engagement piece 67 is guided in a deflected state inside the guide groove 78 of the upper plate portion 74. When a front edge of the base portion 61 is pushed and pressed in until a front edge of the base portion 61 makes contact with the vertical wall 71a of the coupling portion 71, the engagement piece 67 reaches the engagement concave portion 77 and a tip end thereof projects and engages into the engagement concave portion 77 for engagement of the contact point member 60. Therefore the contact point member 60 is sandwiched between the collar portions 76 and the upper plate portion 74 to be positioned and held therein, and the engagement between the engagement piece 67 and the engagement concave portion 77 prevents the contact point member 60 from falling down.
However, in the conventional mounting structure of the contact point member, the base portion 61 of the contact point member 60 is pushed and pressed in the narrow clearance between the upper plate portion 74 and the collar portions 76 in the base member 70 in a sliding direction over a relatively long distance at the mounting operation and advances with the engagement piece 67 being deflected during the sliding movement. Therefore a relatively high pushing and pressing force is required.